I tend to agree to some extent and for devices with little RAM I stop updating them before Apple does in general (2GB RAM devices should be stopped at 13 for my standards, 3GB devices at 15, but anything with 6 or 8 I would upgrade till the end).I think iPads’ longevity is wildly underrated for content consumption. To add to that, older iOS versions are also wildly underrated. I, like you, have the 9.7-inch iPad Pro, which is the 1st-gen (do you have that one or the 12.9-inch?), and it runs iOS 12. iOS 12 is the iPad Air 1’s final version, and it works almost perfectly for content consumption. Some websites have a little trouble, but the vast majority work; streaming apps work (if not all of them, the vast majority); iBooks and reading? Flawless; videos, with YouTube? It works; light gaming works, too.
For this light usage, which I would guess that it’s what the most people use iPads for, you can practically use any iPad that runs iOS 12 onwards, and if you want to play it a little safer, we could even say that the iPad Air 2 onwards are perfectly suitable for this purpose. You don’t need an M1 to do that.
Many people believe that you need the iPad to support (or have!) the latest version for it to be able to do anything, and that couldn’t be further from the truth.
Having said that sometimes a great new app arrives and you cannot install it because it requires the latest (which is not the case for the OP, who only needs basic stuff).
For instance DaVinci Resolve requires iPadOS 16.
A recent great PDF app arrived on iPad (was already the best on Windows) and it requires 15 (Drawboard PDF).
Having said that the opposite has also happened.
A music app I use a lot stopped working on 16 and the developer has not cared to update it despite the complaints.
These issues will only increase in time, but for low RAM devices I am willing to take the compromise to keep them responsive and avoid too many reloads.